10,200 research outputs found

    A comparison of variable valve strategies at part load for throttled and un-throttled SI engine configurations

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    The presented work concerns the study of the fuel consumption and emissions benefits achieved at part load by employing a fully variable valve train in a 1.6L SI gasoline engine. The benefits achieved when using variable valve timing alone, and combined with an early intake closing strategy for un-throttled operation were explored in order to highlight the merits of throttle versus un-throttled engine operation in conjunction with variable valve timing and lift. In addition, particular interest was given to the presence of internal Exhaust Gas Recirculation (EGR) and its ability to reduce pumping loss at part load. An engine model employing multiple sub models to handle variable valve operation was constructed using a commercial gas dynamics engine code, allowing detailed analysis of three valve strategies. Using the engine model, a theoretical study validated by experimentally available data was carried out to study key valve timing cases. A detailed breakdown of the mechanisms present in each case allowed a comprehensive understanding of the influence of valve timing on gas exchange efficiency and fuel consumption

    Controlled Experiments

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    Subjective information visualizations

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    Information Visualizations (InfoViz) are systems that require high levels of cognitive processing. They revolve around the notion of decoding and interpreting visual patterns in order to achieve certain goals. We argue that purely designing for the visual will not allow for optimum experiences since there is more to InfoViz than just the visual. Interaction is a key to achieving higher levels of knowledge. In this position paper we present a different perspective on the underlying meaning of interaction, where we describe it as incorporating both the visual and the physical activities. By physical activities we mean the physical actions upon the physical input device/s. We argue that interaction is the key element for supporting users’ subjective experiences hence these experiences should first be understood. All the discussions in this paper are based upon on going work in the field of visualizing the literature knowledge domain (LKDViz)

    Haptic Experience and the Design of Drawing Interfaces

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    Haptic feedback has the potential to enhance users’ sense of being engaged and creative in their artwork. Current work on providing haptic feedback in computer-based drawing applications has focused mainly on the realism of the haptic sensation rather than the users’ experience of that sensation in the context of their creative work. We present a study that focuses on user experience of three haptic drawing interfaces. These interfaces were based on two different haptic metaphors, one of which mimicked familiar drawing tools (such as pen, pencil or crayon on smooth or rough paper) and the other of which drew on abstract descriptors of haptic experience (roughness, stickiness, scratchiness and smoothness). It was found that users valued having control over the haptic sensation; that each metaphor was preferred by approximately half of the participants; and that the real world metaphor interface was considered more helpful than the abstract one, whereas the abstract interface was considered to better support creativity. This suggests that future interfaces for artistic work should have user-modifiable interaction styles for controlling the haptic sensation
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